Thermostat



Patented Jan. 2, 1940 PATENT OFFICE 2,185,914 7 'rnEaMos'rA'r Max Gaul, Eppstein, Germany, assignor or one-, half to Max Goldschmidt, Frankfort-on-the- Main, Germany Application December 2s, 1936, Serial No. 117,933 In Germany September 2'1, 1934 1 claim. (01. 236-34) The invention relates to thermostats with throttle valves or valve plates for closing the conduits. In known arrangements of this kind, which are used for example in internal combustion engines and stationary Diesel engines, there is the draw-back amongst others that the closure members are opened against the action of the thermostatic element due to the pressure of the cooling water. which is often high. By the present invention this draw-back is avoided by the closing element being driven from the thermostatic element by means of a screw thread which is of steep pitch and therefore self-locking. Further, by combining a multiple steep pitch thread with a single thread a difierential action can be obtained which enables the stroke of the valve plates to'be made considerably greater than would 1 correspond to the expansion of the corrugated tube.- This makes it possible to use shorter corrugated tubes than would otherwise be neces- The invention is illustrated in the accompanying drawing in which Fig. 1 is a longitudinal sectional view of the thermostat in its operative position in an engine cylinder jacket,

Fig. 2 is a top plan view of the thermostat, and Fig. 3 is a cross-sectional view of the thermostat taken along line 3-3 of Fig. 1. 30 Referring to the drawing, A represents generally a water jacket of an internal combustion engine. The thermostat. element is indicated generally at B. As seen in this figure the thermostat element is clamped between the radiator pipe and the water jacket of the internal combustion engine by the upper plate 14 of the thermostatic element while the lower part of the thermostat is connected to the so-called short cir- V cult pipe leading directly to the water pump 4" of the engine.

Referring more particularly to the thermostat element, reference characters 2 and'3 represent two passages formed by quadrant-shaped openings inplates l4 and I! connected together by 45 means of stirrups 'l, the openings 2 and 3 being closable alternately by similarly shapedrotatable valve plates 4 and-5. These are mounted on the separate axles l0 having one end thereof secured to each end wall of the thermostatic element.

50 The thermostatic element 6 is arranged so as to rotate with the axles Ill and is disposed approximately in the middle position between the plates Il and I1 and the axle 10 has at the upper end a multiple steep' pitch thread l2 and at the lower 55 end a single low pitch thread I5. Nuts l3 and 16, corresponding to the two threads are secured in the two plates l4 and N. If the thermostatic element 6 expands the steep pitch thread I! is pushed forward in the nut i3 and the axle l0 1 together with the thermostatic element 6 and g the valve plates 4 and 5 rotate in clockwise direction if viewed from the bottom ofthe device-and will simultaneously cause the single thread Hi to move plate 5 from plate II. By these means there is obtained between thedifierence in pitch in of the two threads I2 and IS a differential action which simultaneously efiects the lifting of the valve plates 6 and 5 from their respective seatings. The figures in the drawing show the thermostatic element as open at the top of the device 15 and closed at the bottom. When the thermostatic element 6 assumes an expanded position, the valve 4 moves on its seat 2 to a closed position while at the same time the plate'E at the bottom of the device is lifted away from its seat 24) 3, the plate 5 being lifted from seat 3 by the movement of the threaded portion IS.

The operation of the thermostatic element is as follows: As long as the cooling water has the external temperature the throttle valve 5 takes 25 up a position in which the cooling water for rapid heating passes through the opening 3 into the so-called short-circuit pipe to the pump and back into the water jacket of the engine. As soon as the cooling water is heated to about 70 the thermostatic element begins to expand and pushes the threaded part of the axle it acting asa thrust-rod over the threaded pin i2 and thereby is rotated together with the throttle valve 6 and the thermostatic element 6.

Sincethe steep pitch thread 12 is self-locking the rotation cannot occur accidently, for example under the influence of the flow pressure formation of eddies and the like.

It is to be understood that the form of the in-' 40 vention'shown and described herewith is to be taken as an example of the same, and that various changes in the shape, size and arrangement of parts maybe resorted to without departing,

from the spirit of the invention, or the scope of the following claim.

What I claim is:

A thermostatically controlled means for regulating the flow of fluid in accordance with temperature variations, comprising-a casing having an inlet and a pair of outlet openings for the passage of fluid, a thermostatic element arranged in the casing between the inlet and outlet openings, a threaded member secured to each end of said thermostatic element, the pitch of the threaded portion of one 01' the members being greater than the pitch of the threaded portion of the other member, a valve secured to each of said members to by-pass the fluid and controlled by the expansion and contraction of said element, a pair of spaced threaded. bearings carried by the casing and having threaded engage- 'ment' with the threaded portions of said memmembers by the expansion and contraction of 5 the thermostatic element.

MAX GAUL. 

